Help with my camera

Hi! I apologize for dumping this on you girls, but google isn't helping me. I figured maybe there is an easy fix to my problem (probably), but I know nothing about my camera.

I have a Canon xsi. I don't know how to use it, so I always use the auto setting. I just returned from a trip & suddenly, I can't take pictures unless the object is very far away. No close-ups of the kids, not even a good photo from 4 feet away. It seems if I back up about 6 feet, it will take a picture, but obviously, this is not ideal.

Any idea what is going on or what crazy setting I might have accidentally pushed? I hate to take it to a camera repair shop if it's an easy fix.

Once my camera was having trouble focusing, and it turned out there was just a big smear on the lens, lol. I didn't notice because the lens hood was on. My son must have wiped something on there You could try checking that, otherwise, I have no suggestions. Good luck!

Have a quick suggestion but please forgive me as I don't know the technical names for the parts. I also work with Nikon and don't know what lens you are currently using. But I googled a quick image of a 50mm lens to show you what I mean. http://blog.warehouseexpress.com/the-50mm-lens/

check your lens and see if you have a little switch like the one that is on the left pic under the numbers 1:1.8D obviously depending on which lens you are using yours may be in a different location but try seeing if you have one and sliding it to the opposite position, you may have to turn the lens to get it into place. Sorry to be so vague like I said I forget exactly what its called but something similar happened when I first got my cam and thats what it was.

After some extensive google research, I figured out that it was the autofocus feature in the lens itself that was broken. Ordered a new one & received it today. That was the problem! Thankfully, the camera is covered under our insurance, so they are reimbursing us for the lens!